The teenage gunman and an instigator of the killing were sentenced in 2012 but an appeal court overturned the verdict. An indictment prepared in late 2015 accused the officials now on trial of running a criminal network, destroying evidence, dereliction of duty and official misconduct.

Their case has been combined with the murder retrial.

The EU, which Turkey hopes to join, has criticised the slow pace of the prosecution and expressed concern about impunity for law enforcement officials in general.

“This is an important day. We have been working for nine years to see these police and intelligence chiefs in court,” Garo Paylan, an opposition lawmaker and member of Istanbul’s Armenian community, said outside the courthouse.

“We wanted to see other public figures here but ... if the court does its job, I believe we will get closer to the truth.”

Among the defendants are Engin Dinç, head of intelligence for the national police, his predecessor Ramazan Akyürek, former Istanbul police chief Celalettin Cerrah and Istanbul police’s former intelligence chief Ali Fuat Yılmazer. They deny wrongdoing.

Some of those on trial were previously accused of involvement in leaking details of a corruption investigation into President Tayyip Erdoğan’s inner circle in 2013 when he was prime minister.

The corruption investigation was later shelved and opposition MP Sezgin Tanrıkulu said Tuesday’s trial was an attempt to settle scores.

“One side of a power struggle is on trial here,” he said at the courthouse.

Dink saw his role as a journalist as a way to improve dialogue between Turks and Armenians and eradicate the taboo of discussing the genocide, whose 101st anniversary will be marked on 24 April.